Aeration Module

L. Gregory Brenneman

A look at how to maintain stored grain in good, quality condition, we’ll see how three different conditions interact to cause grain spoilage problems. This grain module is brought to you by the Iowa Grain Quality Initiative and was produced by the Crop Advisor Institute.

Learning objective: Understand the function of aeration in preventing grain spoilage. Learn to establish a grain quality monitoring system with frequent temperature checks to prevent spoilage.

Introduction: In order to maintain grain in good quality condition, it’s important to avoid storage problems. There are three areas to focus on: moisture, temperature, and time. Holding grain that is too wet, too warm, or for too long can cause problems. This module explains how those three different conditions interact to cause grain spoilage. In addition, the accumulation of fines can promote spoilage or restrict airflow. This module will present solutions, including how aeration prevents uneven grain temperatures during moist conditions in storage, and the importance of checking grain while it is in storage to prevent small problems from developing into large ones.

Moisture: Fungi and other spoilage organisms grow best at or above 65 percent relative humidity. The air within stored grain should stay below 65 percent relative humidity if possible to prevent spoilage. For wetter corn, temperature becomes the primary control factor.

Temperature Control: Moisture migration can cause crusting or spoilage at the top of the bin near the center. Moisture migration can be prevented by cooling the grain with aeration fans. Aeration fans create a negative pressure system pulling cool air down through the grain or a positive pressure system by pushing cool air up through the grain. There are a variety of electronics available to measure grain temperature and monitor the aeration process.

Checking Grain Storage: Stored grain needs to be checked to monitor grain quality. During the winter months, checking every other week is adequate. Checking once per week during summer, spring, and fall is recommended. Safety should be a priority when checking stored grain. Depending on the severity of the spoilage, correcting a storage problem can be done by aeration fans or grain removal.